The prior art is already aware of various configurations and arrangements of seals for track chains, and like assemblies. These assemblies are commonly known and used in connection with track chains for crawler-type tractors, and the chains have the usual pins and bushings and links. The concern and problem with these assemblies is to seal against the entry of dirt between the moving parts of the chain, and to also seal against the exit of lubricant. Examples of these track chains are shown in U.S. Pat. Nos. 2,911,840 and 3,336,086 and 3,347,602 and 3,595,572 and 3,622,165 and 3,680,924 and 3,731,551. The aforementioned all show the crawler type of track chain and they show elastomeric types of seals employed in the chains. Also, U.S. Pat. No. 3,341,259 shows a crawler type of track chain with an elastomeric seal having annular or ring members on each end of the seal. However, the overall arrangement, and also the particular configuration and arrangement of the seal itself, is patentably distinguishable from the arrangement and seal disclosed herein. The aforementioned is true since the arrangement in the present invention is such that the seal is effective between the bushing and the pin, to thereby fully and completely seal against the entry of dirt and the exit of lubricant between the bushing and chain pin.
Further disclosures of prior assemblies and seals as related to track chains are shown in my U.S. Pat. No. 3,948,574 and in my U.S. patent application Ser. No. 618,438, filed Oct. 1, 1975 and entitled "Sealed Track Joint".
Accordingly, the present invention provides a sealed track chain joint which is a general improvement upon the prior art and which provides a complete and positive seal between the track chain pin and the bushing thereon, such that the surfaces between the pin and bushing are completely and positively sealed.
Further, it is an object of this invention to provide a sealed track chain joint which incorporates an elastomeric member which is capable of flexing, including a torsional type of flexing on the cylindrically-shaped elastomeric member itself, to permit the pin and bushing of the chain to rotate relative to each other in the normal manner and in the normal use of the track chain, all while the seal serves its desired function of excluding the dirt and preventing the escape of lubricant from the joint.
Still further, the present invention provides a sealed track chain joint which utilizes a thrust washer, as a part of the seal itself, and the thrust washer is disclosed as being press-fitted onto the pin and provides the thrust bearing surface for the end surface of the bushing which is rotatable on the pin. With this arrangement, the seal is fully and positively effective as a seal, and the thrust bearing washer is available for alignment of the members of the track chain, such as the bushing itself and the link which is piloted on the bushing. Also, the present invention provides the sealed track chain joint with a ring press-fitted onto the bushing, and with an elastomeric portion of the seal extending between the thrust washer and the ring and to thereby positively prevent a seal between the pin and the bushing so that no dirt can enter therebetween and no lubricant can escape therefrom.
Still further, the present invention provides a sealed track chain joint which can be readily adapted to most standard track chain assemblies, and the seal itself is simply located in a counterbore in one of the track chain links, and it extends to the bushing rotatable on the pin on which the bushing is piloted. Accordingly, the track chain joint of this invention can be readily and easily adapted to most standard chain assemblies with only a minor, if any, modification of the standard assembly.
Other objects and advantages will become apparent upon reading the following description in light of the accompanying drawings.